Having non-destructive editing and all objects are scalable vectors that offer bit depth independence was in TIFFany 3.0 back on NeXTSTEP in 1996. I actually demoed it as an Apple Engineer from NeXT to the Adobe Devs who later incorporated it into Illustrator and Photoshop.

Having the ability to truly work with such functionality would give MyPaint a huge presence in scene development for Games, Motion pictures, etc. You would want a live edit view with minimal post processing and a post process view for final output. Not having the ability to treat all objects as scalable and independent is one of the reason Inkscape was developed. However, they have a lot of limitations in that application. To build upon libraries and cross service functionality between GIMP, Inkscape and MyPaint would be a big selling point for FOSS.

On OS X working in Affinity Designer and Photo, with Pixelmator allows for a great work flow. Vector Brushes in Affinity Designer is something that would make MyPaint an obvious choice to have. The traditional painting of MyPaint is awesome. It just needs that added underlying large functionality to be an indispensable tool in more market segments.

However, I would first coordinate with GNOME/KDE and Linux proper to get a much broader range of Tablet/Pen functionality to not only recognize the USB device, but actually leverage the hardware and use it as designed.

Like Wacom, Huion should be built into GNOME and KDE. As of now, it's hit n' miss.

MyPaint needs a proper port to OS X that GIMP already has done. Elle Stone and Partha seem to be the folks to work with to get it done.

Long-term, I would love to see Blender, GIMP, MyPaint and Inkscape as a quartet of tools used along side Adobe's traditional suite.

Final Cut Pro/Motion/Logic and Adobe Premiere will never lose to any FOSS platform. The previously mentioned quartet has the best shot of garnering major financial backing, while maintaining your core ethos on licensing, if you can collaborate together more completely.

The bucket tool is not very good on its own leaving many white dots. Plus you cant just select a general area and move it with it either. Selection tools are in almost every paint program out there and is even considered a basic tool in painting and one of the most used. Just having it would save a lot of time. For instance lets say you drew someting really good and had to move it but forgot to put it in a new layer. Well SCREW YOU YOU HAVE TO UNDO IT ALL AND START ALL AGAIN HAHAHA

I'd probably use selection tools sometimes. But MasonMac, for your two issues so far, here are workarounds:

The bucket is actually pretty good IF you use hard pixel brushes (at least for the inside of the area you want to bucket fill). You can make a new layer (or copy a layer) and use that to paint up regions to bucket. (That said, bucket filling I often do in another program most of the time -- my workflow is sketch in mypaint, flatten in other apps, color in mypaint.)

And for wanting to move something but it's in the same layer as something else good: copy the layer! in one layer, erase the good thing, in the other layer, erase everything except tthe good thing.

All of that said, if you want to love MyPaint you sooner or later have got to get comfortable with using other tools. It sucks that GIMP's ora support is so lacking. But. Usually you can do what you want to do with a little work and ingenuity.

Honestly... I agree actually, that selection tools would be useful. One thing I use a LOT in MyPaint is this construct: a layer group with two layers. The top layer in the group uses Destination In, the bottom layer is normal. And then I paint on the bottom layer. The top layer is sort of the "selection". I set this up via scripts (doing it manually like PeterToybulldog does, that's unreasonable since I often have twenty, thirty layer groups like this). But... it's still cumbersome.

I usually use svg layers for these top "mask" layers, and a paintable raster layer for the bottom "paint" layer in each group. For example I might make a hand outline in Inkscape, put it as the "mask" (Destination In) layer, and then I can paint the hand underneath it on the "paint" raster layer.

But setting it up by hand, setting the blend modes, creating the masks etc, that's such a hassle compared to Manga Studio where you can just have a flatted image, select with wand on a selection layer and then paint within that selection (a la Destination In) on a paint layer.

Since I use MyPaint, I have scripts that set up these "Destination In" layer groups to "emulate" saved selections. Generating the ora files. But, they become big and slow.